add getSiteConfig

lib/apis.js

@@ -165,6 +165,15 @@ module.exports.create = function (xconfx, apiFactories, apiDeps) {
             }
           });
 
+          Object.defineProperty(req, 'getSiteConfig', {
+            enumerable: true
+          , configurable: false
+          , writable: false
+          , value: function getSiteMailerProp(section) {
+              return PromiseA.resolve((siteConfig || {})[section]);
+            }
+          });
+
           Object.defineProperty(req, 'getSitePackageConfig', {
             enumerable: true
           , configurable: false